Channel culture devices which provide multiple plant growth channels of indefinite length but of shallow depth and narrow individual width have the most potential for increasing the world's food supply. These channels provide maximum plant production for a given supply of fertile soil, water, fertilizer and insecticide, some or all of which are scarce and at an extreme premium at many parts of the world. The growth channels have a limited volumetric area that can be made just sufficient for the full root development of any specified plant so that optimum availability of nutrients and water to the plant is obtained. Further the isolation of the channels prevents the leaching and escape of the available supply of nutrients and water into the underlying soil. Isolation also simplifies the problems of cultivation and of the control of pests, disease, and weeds.
Various design proposals have been made, of which some are disclosed and claimed in my co-pending U.S. Patent Application Ser. No. 512,518 now abandoned filed Oct. 7, 1974 for "Channel Culture Device" and in my recently issued U.S. Pat. No. 3,987,585 issued Oct. 26, 1976 for "Modular Channel Culture Device".
Many modular configurations have thus been suggested. It has been found in practice that most modular channel configurations incur two major drawbacks. Typically they are of a predetermined size and to achieve flexibility of sizes within a particular total assembly has proved cumbersome and expensive. Modular plant devices which have the ability to be extended both in length and breadth through some type of interfitting or interlocking connections have not exhibited the necessary structural flexibility to readily form modules of various sizes.
Further, most configurations have resulted in an environment for containing and supporting the plants and plant support systems which allow a modest amount of flow of water downwardly from the top surface and along the walls. Lateral flow of air and water into and from the plant support system in a channel as a practical matter, did not occur. These concepts were then felt not to be important in that the total amount of nutrients required to maximize plant growth could be carefully controlled since there would generally be no leaching from the culture device. It has been found that this non-leaching concept although theoretically sound, had attendant problems which in many instances outweighed the advantages. For example, when used in small scale, i.e. home, small garden areas, etc. there is a tendency by the user to over water or over feed. The accumulated water could not drain properly, being sealed on three sides, and this condition deleteriously affected plant growth. In large scale operations unexpected rain fall results in the same problem.
My recent work in this area has established that the concept of increased aeration of the plant support system while providing some structure to minimize complete leaching has overcome the aforementioned problems.